671736321 has 28 divisors (see below), whose sum is σ = 1050958848. Its totient is φ = 428342904.

The previous prime is 671736319. The next prime is 671736379. The reversal of 671736321 is 123637176.

671736321 is a `hidden beast` number, since 6 + 7 + 17 + 3 + 632 + 1 = 666.

It is not a de Polignac number, because 671736321 - 2¹ = 671736319 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (671736301) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 3265 + ... + 36798.

Almost surely, 2^671736321 is an apocalyptic number.

It is an amenable number.

671736321 is a deficient number, since it is larger than the sum of its proper divisors (379222527).

671736321 is an equidigital number, since it uses as much as digits as its factorization.

671736321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40104 (or 40089 counting only the distinct ones).

The product of its digits is 31752, while the sum is 36.

The square root of 671736321 is about 25917.8764755140. The cubic root of 671736321 is about 875.7892507654.

The spelling of 671736321 in words is "six hundred seventy-one million, seven hundred thirty-six thousand, three hundred twenty-one".